Avoid markup text memory leak in wxStaticText

Add forgotten destructor.

This should have been even more part of hastily pushed 0f26d71 (Merge
branch 'msw-stattext-markup', 2024-12-12), see wxWidgets#25000.

include/wx/msw/stattext.h

@@ -34,6 +34,8 @@ class WXDLLIMPEXP_CORE wxStaticText : public wxStaticTextBase
                 long style = 0,
                 const wxString& name = wxASCII_STR(wxStaticTextNameStr));
 
+    virtual ~wxStaticText();
+
     // override some methods to resize the window properly
     virtual void SetLabel(const wxString& label) override;
     virtual bool SetFont( const wxFont &font ) override;

src/msw/stattext.cpp

@@ -61,6 +61,13 @@ bool wxStaticText::Create(wxWindow *parent,
     return true;
 }
 
+wxStaticText::~wxStaticText()
+{
+#if wxUSE_MARKUP
+    delete m_markupText;
+#endif // wxUSE_MARKUP
+}
+
 WXDWORD wxStaticText::MSWGetStyle(long style, WXDWORD *exstyle) const
 {
     WXDWORD msStyle = wxControl::MSWGetStyle(style, exstyle);